Power control apparatus and power control method

Abstract

A power control apparatus includes: a control unit that controls discharged power of a first battery and discharged power of a second battery; and a power acquisition unit that acquires a total power to be supplied from the first and second batteries to a load device connected to the first and second batteries. The control unit: in a first period, changes the discharged power of the first battery according to a change in the acquired total power, and changes the discharged power of the second battery toward a first direction in which the discharged power of the second battery approximates the discharged power of the first battery; and, in a second period after the first period, changes the discharged power of the second battery according to the change in the acquired total power, and changes the discharged power of the first battery toward a second direction opposite the first direction.

The invention claimed is: 
     
       1. A power control apparatus of a solar power generation system, comprising:
 a control unit configured to control a discharged power of a first storage battery and a discharged power of a second storage battery; and 
 a power acquisition unit configured to acquire a total power to be supplied from the first storage battery and the second storage battery to a load device connected to the first storage battery and the second storage battery, 
 wherein the control unit is configured to:
 in a first period, change the discharged power of the first storage battery according to a change in the total power acquired by the power acquisition unit, change the discharged power of the second storage battery toward a first direction which is a direction in which the discharged power of the second storage battery comes close to the discharged power of the first storage battery, and thereby keep a sum of the discharged power of the first storage battery and the discharged power of the second storage battery equal to the total power acquired by the power acquisition unit; and 
 in a second period after the first period, change the discharged power of the second storage battery according to the change in the total power acquired by the power acquisition unit, change the discharged power of the first storage battery toward a second direction which is a direction opposite the first direction, and thereby keep a sum of the discharged power of the first storage battery and the discharged power of the second storage battery equal to the total power acquired by the power acquisition unit. 
 
 
     
     
       2. The power control apparatus according to  claim 1 ,
 wherein the control unit is configured to: 
 in the first period, change the discharged power of the second storage battery toward the first direction by increasing the discharged power of the second storage battery from 0; and 
 in the second period, change the discharged power of the first storage battery toward the second direction by decreasing the discharged power of the first storage battery to 0. 
 
     
     
       3. The power control apparatus according to  claim 1 ,
 wherein the control unit is configured to: 
 in the first period, change the discharged power of the second storage battery toward the first direction by increasing the discharged power of the second storage battery at a first rate; and 
 in the second period, change the discharged power of the first storage battery toward the second direction by decreasing the discharged power of the first storage battery at a second rate. 
 
     
     
       4. The power control apparatus according to  claim 1 ,
 wherein the control unit is configured to stop changing the discharged power of the first storage battery according to the change in the total power, in a third period between the first period and the second period. 
 
     
     
       5. The power control apparatus according to  claim 4 ,
 wherein the control unit is configured to, in the third period, stop changing the discharged power of the first storage battery according to the change in the total power, and change the discharged power of the first storage battery toward the second direction. 
 
     
     
       6. The power control apparatus according to  claim 4 ,
 wherein the control unit is configured to, in the third period, change the discharged power of the second storage battery toward the first direction. 
 
     
     
       7. The power control apparatus according to  claim 4 ,
 wherein the control unit is configured to stop changing the discharged power of the first storage battery according to the change in the total power, after an elapse of a predetermined period from a start of the third period. 
 
     
     
       8. The power control apparatus according to  claim 4 ,
 wherein the control unit is configured to control the discharged power of the first storage battery and the discharged power of the second storage battery and thereby keep a sum of the discharged power of the first storage battery and the discharged power of the second storage battery constant from when the control unit stops changing the discharged power of the first storage battery according to the change in the total power to when the second period starts. 
 
     
     
       9. The power control apparatus according to  claim 1 ,
 wherein the power acquisition unit is configured to acquire the total power from the discharged power of the first storage battery, the discharged power of the second storage battery, and an excess or deficiency of power supply to the load device in relation to electric power consumed by the load device. 
 
     
     
       10. A power control method for a solar power generation system, comprising:
 controlling a discharged power of a first storage battery and a discharged power of a second storage battery; and 
 acquiring a total power to be supplied from the first storage battery and the second storage battery to a load device connected to the first storage battery and the second storage battery, 
 wherein in the controlling:
 in a first period, the discharged power of the first storage battery is changed according to a change in the total power acquired in the acquiring, the discharged power of the second storage battery is changed toward a first direction which is a direction in which the discharged power of the second storage battery comes close to the discharged power of the first storage battery, and a sum of the discharged power of the first storage battery and the discharged power of the second storage battery is thereby kept equal to the total power acquired in said acquiring; and 
 in a second period after the first period, the discharged power of the second storage battery is changed according to the change in the total power acquired in the acquiring, the discharged power of the first storage battery is changed toward a second direction which is a direction opposite the first direction, and a sum of the discharged power of the first storage battery and the discharged power of the second storage battery is thereby kept equal to the total power acquired in said acquiring. 
 
 
     
     
       11. A non-transitory computer-readable recording medium for use in a computer, the recording medium having a computer program recorded thereon for causing the computer to execute the power control method according to  claim 10 . 
     
     
       12. An integrated circuit of a solar power generation system, comprising:
 a control unit configured to control a discharged power of a first storage battery and a discharged power of a second storage battery; and 
 a power acquisition unit configured to acquire a total power to be supplied from the first storage battery and the second storage battery to a load device connected to the first storage battery and the second storage battery, 
 wherein the control unit is configured to:
 in a first period, change the discharged power of the first storage battery according to a change in the total power acquired by the power acquisition unit, change the discharged power of the second storage battery toward a first direction which is a direction in which the discharged power of the second storage battery comes close to the discharged power of the first storage battery, and thereby keep a sum of the discharged power of the first storage battery and the discharged power of the second storage battery equal to the total power acquired by the power acquisition unit; and 
 
 in a second period after the first period, change the discharged power of the second storage battery according to the change in the total power acquired by the power acquisition unit, change the discharged power of the first storage battery toward a second direction which is a direction opposite the first direction, and thereby keep a sum of the discharged power of the first storage battery and the discharged power of the second storage battery equal to the total power acquired by the power acquisition unit.